By Amy Tennery
NEW YORK (Reuters) - Betting exchanges and online trading platforms on Tuesday said Democratic presidential candidate Hillary Clinton held a far higher probability of winning than Republican Donald Trump.
While Trump made modest gains in probability to win on some online platforms as Americans went to the polls on Tuesday, many gave Clinton a better than 75 percent chance of victory.
Bookmaker Paddy Power said Clinton's chance of taking the White House dipped slightly to 81.8 percent on Election Day from 83.3 percent, while Trump's probability improved to 22 percent from 20 percent.
"The flow of money is relatively even with it slightly favoring Trump," said Paddy Power spokesman Féilim Mac An Iomaire.
He said Paddy Power has seen at least 20 four- and five-figure bets placed on Tuesday. Different bookmakers and exchanges have different closing times for placing bets.
Record numbers of bettors are pouring millions into online platforms in the hope of capturing a financial windfall from the election.
British gambling company Ladbrokes, which has Clinton's chance of winning at 76 percent and Trump's at 24 percent, said it anticipated more wagers coming in for the outcome of the U.S. presidential election than had been placed on the European Union referendum - or "Brexit" vote.
"The U.S. election has gripped the nation," said Ladbrokes spokeswoman Jessica Bridge in a written statement. "It [is] the biggest ever non-sporting event the bookmaking industry has witnessed."
British-based internet betting exchange Betfair's "Next President" market was on track to surpass Brexit in amount traded, owing to the surprise results of the referendum that were still fresh in many Britons' minds, spokeswoman Naomi Totten said.
The market saw just under $150 million wagered since it opened in November 2012, with $7 million traded in just seven hours on Tuesday.
While opinion polls went back and forth leading into Britain's June 23 referendum on whether or not to remain in the European Union, betting odds favored the "remain" campaign. Britons voted to leave by a 52 percent to 48 percent margin.
Clinton is trading at an 80 percent chance on Betfair and Trump at a 20 percent chance of winning the White House.
Trading platforms in the United States showed similar probabilities.
On PredictIt, launched in 2014 and jointly run by Victoria University in Wellington, New Zealand, and Washington, D.C.-based political consulting firm Aristotle International Inc, Clinton had an 80 percent chance of victory down from 81 percent Sunday, while Trump was at 22 percent, up from 20 percent.
(This story corrects to say opinion polls went back and forth on 'Brexit' vote instead of most opinion polls predicted Britons would choose to remain in EU, paragraph 11)
(Reporting By Amy Tennery; editing by Grant McCool)